<?=class::$lang[$this->lang]['_key_']?> Not working

Hello, I god very weird problem on cent os server. I use php templates on TYPO3 based system. which uses short tags some how <?=class::$lang[$this->lang]['_key_']?> was not working. System works perfectly on my ubuntu machine. Another problem was. I can get $this->lang I can get print_r(class::$lang) but I cannot access them. Another weirdness was some parts of the script can get class::$lang[$this->lang]['_key_'] values Does anybody give me clue ? PS: This code 4th or 5th level deep require. Is there any ini parameter for this ? Regards Sancar